Why would it be running so cool?

[Kawana]

I just did a coolant flush and cleared a blockage from the radiator. It was running cool before all of that, so I replaced the thermostat with a 185* thermostat, but its still only hittin 150*. The upper rad hose gets hot, but not so hot that I cant hold onto it. Why would it be running so cold? Could it be a faulty the temp sensor? Would a build up of crud within the engine coolant passages do this?

 

[beardeddummy]

My truck idled for 45 minutes with a 195 thermostat new ect. 179 was all I seen on the scanner

 

[superdave]

What are you using to judge temp? If it's the gauge, they have been known to be less than accurate. Get a laser gun thermometer. It should be in every tool box.